When you go to report anything like this please consider-

On default settings you share files as you download them. This means that the person you are about to report has not even finished downloading the file yet and might have no idea what's on it. Someone else might report you, while you were downloading; they downloaded off you, and so on..........

Miss clicked a download, could happen. Asleep at the moment but will be horrified tomorrow when downloads are checked and the file is found.

I think the only way you could be sure is if you browsed host and saw a pile of these types of files.